Borah Dipu, Satokawa Shigeo, Kato Shigeru, Kojima Toshinori
Department of Materials and Life Science, Faculty of Science and Technology, Seikei University, 3-3-1 Kichijoji Kitamachi, Musashino-shi, Tokyo 180-8633, Japan.
J Colloid Interface Sci. 2008 Mar 1;319(1):53-62. doi: 10.1016/j.jcis.2007.11.019. Epub 2007 Dec 21.
This paper reports the results of the adsorption performance of As(V) removal by a commercial carbon black and its H2SO4-modified form in a single-ion situation. The influence of different process parameters and the physicochemical principles involved were studied in detail. Acid modification caused morphological changes in the virgin carbon black as evidenced by BET surface area measurements and SEM study. FTIR spectra showed the introduction of sulfonic acid group in the parent carbon due to H2SO4 treatment. TGA analysis revealed higher weight loss characteristics of the modified carbon, demonstrating the creation of functional groups. The point of zero charge (pH pzc) of the modified carbon black is highly acidic (3.5) compared to commercial carbon black (6.4). It directly infers the generation of acidic functional moieties in the carbon black. The adsorption experiments were carried out following batch equilibrium techniques. The kinetics and thermodynamics of adsorption were investigated to unveil the mechanism and nature of the adsorption process, respectively. The kinetic parameters of different models were calculated and discussed. The kinetics of adsorption can be expressed by a pseudo-second-order model and intraparticle diffusion was not the rate-determining step. Dependence of pH on adsorption showed maximum metal uptake in the range of 4-5 and inferred surface complexion as the principal mechanism of adsorption. The equilibrium adsorption data were modeled using Freundlich, Langmuir, and Dubinin-Kaganer-Radushkevich (DKR) isotherm equations and the corresponding isotherm parameters were calculated and discussed in detail.
本文报道了一种商用炭黑及其硫酸改性形式在单离子情况下对五价砷（As(V)）的吸附性能研究结果。详细研究了不同工艺参数的影响以及所涉及的物理化学原理。通过BET表面积测量和扫描电子显微镜（SEM）研究表明，酸改性导致原始炭黑的形态发生变化。傅里叶变换红外光谱（FTIR）显示，硫酸处理使母体炭黑中引入了磺酸基团。热重分析（TGA）表明改性炭具有更高的失重特性，证明了官能团的形成。与商用炭黑（pH pzc为6.4）相比，改性炭黑的零电荷点（pH pzc）呈强酸性（3.5）。这直接推断出炭黑中产生了酸性官能团。吸附实验采用间歇平衡技术进行。分别研究了吸附的动力学和热力学，以揭示吸附过程的机理和性质。计算并讨论了不同模型的动力学参数。吸附动力学可用准二级模型表示，颗粒内扩散不是速率决定步骤。pH对吸附的影响表明，在4-5的范围内金属吸附量最大，并推断表面络合是主要的吸附机理。用Freundlich、Langmuir和杜比宁-卡根纳-拉杜什凯维奇（DKR）等温方程对平衡吸附数据进行了建模，并详细计算和讨论了相应的等温参数。
